Skip to main content

Full text of "Alaskan glacier studies of the National Geographic Society in the Yakutat Bay, Prince William Sound and lower Copper River regions"

See other formats

miles long and 3 miles wide, and is much less rugged than Knight Island. All of the island is high, the summits rising to elevations of 1800 to 2000 feet, and retaining snow as late into the summer as August; but the island is not known to contain any glaciers, although we suspected the presence of a small glacier in one of the snow-filled cirques on the northwestern side, near Dangerous Passage. There are a few large cirques, and the rugged group of summits apparently have been sharpened by local glaciation.
Latouche Island. Latouche Island, south of Knight Island, with its southern end in the Pacific Ocean, is 12 miles long, 2 to 3$ miles wide, and has peaks 1730 to 2225 feet high, some of which retain snow rather late into the summer, though none of them are known to support glaciers at present. In former times, however, on the northwestern side of Latouche Island, there were good-sized local glaciers, which excavated great cirques from one to two miles wide, described and mapped by Grant and Higgins.1 The junior author spent several hours on Latouche Island in 1904 and again in 1910. So much snow remained in the cirques in August and September of each year that it seems quite likely that the larger cirques still contain small, inactive, ice masses.
Montague Island. This, the largest island in Prince William Sound, has a total length of over 50 miles and a width of from 3 to 10 miles. It extends northeast and southwest across the mouth of the sound, nearly parallel to the trend of Latouche and adjacent islands, being separated from Latouche and Knight Islands by Montague Strait. The island is mountainous throughout, the highest peaks, including Montague Peak near the eastern end, lying on the ocean side. The mountains rise to elevations of from 3500 to 4500 feet, and one of the higher peaks near the middle of the island reaches 5641 feet.
The higher summits of Montague Island throughout the whole of its length are snowcapped during the entire year, and probably feed a number of moderate-sized glaciers, those on the side toward Prince William Sound being the largest. One or two of these glaciers, in the region south of Green Island, were seen by us from a distance in 1910; but since Montague Island is largely unexplored none of these glaciers have as yet been shown upon a map.
Extensive local glacial erosion on Montague Island is indicated by scores of cirques in the higher parts of the island and by hanging valleys, visible from Prince William Sound. There are also smaller cirques on the southwestern side of the island, showing that local glaciers formerly descended toward the Pacific Ocean.
Hinchinbrook and Hawkins Islands. Hinchinbrook anoV Hawkins Islands, northeast of Montague Island, separate the eastern part of Prince William Sound from the Pacific. Hawkins Island is 22 miles long and 8 to 4£ miles wide. Its highest peaks are 1846 to 2025 feet high and are not known to contain any glaciers, though cirques give evidence of former local glaciation.
Hinchinbrook Island is 22$ miles long and 13 miles wide. The northern part of the island has a low foreland, south of which are peaks from 1427 to 2910 feet high. Several of these peaks retain snow throughout the summer, and there are small ice masses, spoken of by Seton Karr a as "comparatively insignificant glaciers." None of these ice tongues has ever been mapped.
i Giant, U. S. and Higgins, D. F., Bull. 443, U. S. Geol. Survey, 1910, p. 19, Kg. 3, on p. 30, and PI. XII, in pocket. «Seton Karr, H. W., Shores and Alps of Alaska, London, 1887, p. 193.